Walking around with a large amount of cash isn’t advisable anywhere. Fifty to a hundred dollars in local currency is more than enough to cover small purchases and meals. Change your currency in Israel – it can be done easily almost everywhere. But, taking a few extra minutes at the airport to do this is always a good idea. You can also usually use your debit card to withdraw shekels from most ATMs, but make sure you check your bank’s foreign transaction fees and exchange rate.